564
FXUS63 KGRR 121616
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
1116 AM EST Wed Feb 12 2025

.KEY MESSAGES...

- 4-6" of Snow Today

- Additional Snow Expected This Weekend, Then Cold

&&

.UPDATE...
Issued at 1115 AM EST Wed Feb 12 2025

Snow is moving in this morning as the dry air at low levels is
being overcome. Traffic cams show moderate snow in the Muskegon
area at 11 AM. The radar show persistent mesoscale snow banding
in an area of midlevel frontogenetic forcing extending southwest
all the way to eastern Nebraska. As the column becomes saturated,
snow will begin to accumulate and travel conditions will worsen
this afternoon. No changes to the Winter Weather Advisory, but
POPs were raised across the western and central zones the next
couple hours.

&&

.DISCUSSION...
Issued at 226 AM EST Wed Feb 12 2025

- 4-6" of Snow Today

No changes to ongoing headlines for the upcoming snow event. A mid-
level low visible on water vapor imagery across the 4 corners region
will lead to cyclogenesis of a low over the Southern Plains. This
low will eject into the Ohio Valley passing near Cleveland with the
associated deformation driving widespread snow across the CWA. This
looks to be a solid high end advisory event with 4 to 7 inch totals
across much of the CWA. The snow begins early this afternoon,
peaking between 4pm and midnight with snowfall rates of 0.5-0.75
in/hr. These rates will drive poor visibility and snow covered roads
leading to hazardous travel conditions. The synoptic portion of the
snow will taper off from west to east overnight, with lake effect
lingering into the day Thursday. Given that, an extension to the
advisory may be needed for some of our western counties but will
defer that to subsequent shifts as we get closer to that timeframe.

Two important caveats to mention regarding snow totals. First, is
that if the better FGEN driven banding remains sustained over a
better duration and can take advantage of some mid-level
instability, isolated amounts in the 6-9 inch range are possible.
This would be most likely across the east-central CWA towards I69 if
it occurs. Second is across in our northeastern CWA near
Clare/Harrison etc. Easterly flow off of Lake Huron will enhance
snowfall across this region. Can`t rule out some isolated 6-9 inch
snowfall totals in our extreme NE forecast area as a result but low
confidence means a change in headlines is not warranted.

- Additional Snow Expected This Weekend, Then Cold

A brief break in winter weather is expected Friday as surface and
upper-level ridging passes through. The arrival of several lows
across a baroclinic zone Friday night into the weekend marks the end
of the brief period of tranquility. Several periods of synoptically
driven snowfall are expected through Sunday followed by lake effect
snow showers into the early work week.

Several inches of accumulating snow are likely by the time all is
said and done. High confidence (70-90 percent) of at least 3 inches
of snow Friday Night into Saturday thanks to lake enhancement given
the occluding low`s wind field. Some uncertainty exists in the later
half of the weekend as to how much snow occurs. The
amplitude/position of a southern stream wave will drive a surface
low across the Ohio Valley bringing more snow to the region, the
track of which and its associated deformation zone determining how
much snow occurs in this second wave.

All in all, several inches of snow piling up over the weekend brings
the question of travel impacts back into play so monitoring will be
needed. Conditons then get notably colder next week as an arctic
airmass arrives with 850mb temps in the negative 20s. This would
translate to highs in the teens with lows in the singe digits or
colder.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 654 AM EST Wed Feb 12 2025

Predominantly VFR conditions are expected through 18Z although
some patchy MVFR cigs/vsbys are present early this morning. After
18Z IFR vsbys will eventually become more prevalent as widespread
snow develops and increases in intensity. The heaviest snow is
expected to occur from 21Z to 04Z with LIFR vsbys possible during
this time, particularly south and east of GRR. Snow gradually
diminishing after midnight tonight although some areas of IFR cigs
and vsbys may linger past 06Z.

&&

.CLIMATE...
Issued at 240 PM EST Tue Feb 11 2025

Record Daily Snowfall for February 12th:

Grand Rapids: 5.1 inches in 2019
Lansing: 5.0 inches in 1897
Muskegon: 7.6 inches in 2019
Kalamazoo: 7.0 inches in 1985

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Winter Weather Advisory until 7 AM EST Thursday for MIZ037>040-
     043>046-050>052-056>059-064>067-071>074.
MARINE...None.

&&

$$

UPDATE...Ostuno
DISCUSSION...Thomas
AVIATION...Meade
CLIMATE...Ostuno